It is hard for a lot of people to reduce ambiguity in their instructions, to make no assumptions, so that the instruction will achieve the same result no matter who carries it out. That's why programming is difficult. You have to constantly think how someone else (a computer) will interpret you.
Agreed. And I would argue that programming languages give as structured a way to do this unambiguously as we currently have. As languages improve, we can improve what the computer can interpret unambiguously (or at all), but that is a long process.